Objective:
1) Develop integrated multi-tactic weed management programs which will include cover crops, cultural practices, and bio-herbicides for reduced-tillage production systems. 2) Determine the ecological mechanisms by which crop and soil management impact crop and weed establishment and growth processes.

Approach:
A multi-tactic approach will be developed for reduced-tillage corn production that combines the optimum hairy vetch-rye cover crop mixture for suppressing weeds with poultry litter injection that supplements nitrogen required by the crop, but localizes it in space and time to minimize utilization by weeds. Soil properties, mulch characteristics, and weed sizes will be determined that optimize the postemergence destruction of weeds with a high-residue cultivator, minimize disturbance of the surface residue, and maximize soybean yield. Methods will be developed to augment and purify naturally-produced bacterial phytotoxins and test their efficacy as a postemergence herbicide. Basic research will be conducted to increase our understanding of weed suppression by cover crop mulches in relation to potentially allelopathic compounds leached into the soil and their duration of soil activity. Basic research also will be conducted to determine the effect of soil organic matter on mitigating the competitive effects of weeds on crops.